tier 2 winrate

Hi,
I suppose that in every tier, there is an average winrate, some tanks are below it, some tanks are above it. I assume the percentage of draws is 1%, so the average WR is about 49%
I dont understand, why only 3 tanks in tier 2 on the EU server are above 49% WR, and the others are below. Can anyone please explain this to me?
Thanks
p6qwre

Thank you for answer, but i dont think it explains anything. For example, when I play my tier 2 tank in tier 3 battle, there is also a tier 2 tank on the enemy team. I win, he loses. I have 100% wr, he has 0% WR. The avarage is 50%. Repeat this 1000 times and the average WR will still be 50% (minus draws, the average will be 49%). Sometimes, there will be 5 tier 2 tanks in the winning team and only 4 tier 2 in the losing team, but again, in 1000 and more battles, there will in average be exactly the same number of tier 2 tanks in the winning and in the losing team.
But here on vbaddict, the average WR on tier 2 is like 44%. One logical explanation would be, that with tier 2 tank, 6% of games ends with a draw. That is quite possible…The higher the tier is, the less battles ends with a draw…